Friday, June 10, 2011

Lethal Membrane Nanotubes

As recently discussed the cell membrane structure provides a barrier between the cell interior and the external environment and includes a great variety of molecular machines attached to the sandwich structure which is formed by phospholipid molecules in tail-to-tail formation. These hydrocarbon tails, sandwiched in the middle of the membrane, make for a very oily membrane interior which contributes to the cell’s protective barrier.

But such membrane structures are not limited to the cell’s outer boundary. They also serve various purposes inside, and even outside, the cell. And new research is helping us to understand better some of these roles. For instance, as a recent research paper explains, membrane structures can be used to form long, thin nanotubes used by immune cells to reach out and destroy harmful cells:

Membrane nanotubes are membranous tethers that physically link cell bodies over long distances. Here, we present evidence that nanotubes allow human natural killer (NK) cells to interact functionally with target cells over long distances. Nanotubes were formed when NK cells contacted target cells and moved apart. The frequency of nanotube formation was dependent on the number of receptor/ligand interactions and increased on NK cell activation. Most importantly, NK cell nanotubes contained a submicron scale junction where proteins accumulated, including DAP10, the signaling adaptor that associates with the activating receptor NKG2D, and MHC class I chain-related protein A (MICA), a cognate ligand for NKG2D, as occurs at close intercellular synapses between NK cells and target cells.

As described above, like the cell membrane, these membrane nanotubes include a variety of specialized, critical molecular machines.

And why are such nanotubes needed? The researchers hypothesized that such nanotubes might be used to maintain contact with target cells that move around too much:

It is well established that T or NK cells receive a “stop” signal when activated by a target or antigen-presenting cell. However, target cells would not receive an equivalent stop signal; therefore, particularly motile target cells may be able to move away from cytolytic NK or T cells before an effector response has been realized. Hence, one speculative role for nanotubes could be to facilitate cytolytic cells being able to sustain an interaction with target cells that are particularly motile (e.g., other lymphocytes).

More research is required to understand these nanotubes better, but what we do understand reveals a most interesting story. How curious it is that the nanotubes are able to recruit important molecular machines in order to function. And how strange that the nanotubes deploy when required and successfully kill the target cell. Are we really to believe that such structures and functions arose via a sequence of mutations? And that each mutation was random with respect to the need and the final design? And this in spite of the fact that no such sequence of mutations is actually known to us? In fact this seems to be yet another example of nature not cooperating with evolutionary expectations.

The reason that there is such a dearth of comments is not because of the "power" of the post, but the complete rejection of all previous criticisms against exactly this type of argument. It's like spending hours explaining to someone that monkeys didn't become humans, but evolved from the same common ancestor, only to have that person ask "Then why are there still monkeys?" The proper way to answer that question is to just walk away, because it's obviously not a question that they actually want an answer to. It's a proud statement of their own ignorance.

This and other recent posts are equivalent statements of obstinate ignorance.

Peter Wadeck "Yes I do, but then so does Big Bang cosmology. It is also a more reasonable interpretation than all the complexity of life being created randomly."

So you may believe (although I wonder if Cornelius agrees that he has made a metaphysical assumption?). Yet, were you to remove the metaphysical premise that life has 'final designs' then we have a situation where any given species is unlikely to have existed and diversity is a consequence of imprecise DNA reproduction. Yet, given mutational input and a complex environment, it is effectively impossible for diversity not to arise.

The 'randomness' of mutation does not act alone to create the apparent 'design' we see in biology (the shapes of enzymes, or birds beaks curved like flowers); for this the simple filter of selection inevitably acts upon the variation, which has the effect of ensuring that whatever changes the organism still works. Further, none of that apparent 'design' was necessary - none was prespecified. The bird could have fed on the nectar of a different flower; the enzyme would not have become essential if it did not exist. If not those adaptations, something else.

Neal Tedford said... Paul, life was created with top down design not bottom up evolution. This does not imply fixity of species, but variation is limited, such as with the finch beaks from Darwins study. Input from the enivironment causes the bird population to adapt according, but they are still finches and interestly, they can apparently still interbreed. We see this again and again from finches, to fruit flies to dogs... variation with limits, and nothing but evolutionist imaginations contradict this observable fact.

This does not imply fixity of species, but variation is limited, such as with the finch beaks from Darwins study.

Evidence please. What barrier(s) limits variation, and how did you determine those limits? "A fat-headed pastor has never seen macro change in his lifetime" won't work in the scientific community either.

variation with limits, and nothing but evolutionist imaginations contradict this observable fact.

Why do you still think that events which took tens of thousands to millions of years should be observable in their entirety in a few years in the lab? Oh, that's right - you're an idiot.

How then you you explain ring species, such as the ones found in this short video:

http://www.youtube.com/watch?v=CEtnyx0Yo9I

The message from ring species is clear: keep two groups of the same species apart for long enough, and eventually they will lose the ability to interbreed, and thus count as seperate species - even if there is a continuous chain of intermediary sub-species linking them.

Please elaborate on exactly what these 'limits' to variation are. Where are they set? How do you determine them? I'd LOVE to hear you demonstrate this 'observable fact'.

Neal:"Paul, life was created with top down design not bottom up evolution. "

Yet, the patterns in the fossil record provide evidence of a bottom-up process, not a top-down one.

"This does not imply fixity of species, but variation is limited, such as with the finch beaks from Darwins study."

So do you disagree with Cornelius that biology shows evidence of 'final designs' then?

"Input from the enivironment causes the bird population to adapt according, but they are still finches and interestly, they can apparently still interbreed."

Yes, some interbreeding does happen between the Galapagos species, although this happens between certain pairs species more than others. As Ritchies points out, this along with ring species provide evidence for the incremental buildup of genetic barriers to interbreeding. Hence, this also shows evidence of bottom-up and not top-down processes.

"We see this again and again from finches, to fruit flies to dogs... variation with limits, and nothing but evolutionist imaginations contradict this observable fact. "

Evolution does not posit limitless possibilities, only divine creation does. Variation within limits is exactly what we would expect to see over our short life spans. If this were not the case, there would presumably be many more phyla than there are. The problem for you is that there is a nested hierarchy of limitations/canalisation at different taxonomic levels that once again supports a bottom-up process of evolution, and not a top-down process of creation.

Paul said, "Yet, the patterns in the fossil record provide evidence of a bottom-up process, not a top-down one."

No. The fossil record is does not support gradualism. Have you considered the Cambrian Explosion? It is not unique.

You said, "Variation within limits is exactly what we would expect to see over our short life spans. "

That's a convenient plea, but is it does not hold up to the evidence. Species with short life spans and large populations have been studied for years and bacteria are still bacteria, fruit flies are still fruit flies. You have no solid evidence for your statements.

If this were not the case, there would presumably be many more phyla than there are.

No way to know. The number of phyla actually depends on complex historical factors, as well as the taxonomist's personal taste (and currently monophyly, of course). Every single higher taxonomic category (or rank) is purely conventional, they're not real "things" of nature and they don't even have a definition (the taxon name has, not its rank). For example, you can call anything a genus and you will never be wrong. Thus, it is wrong to count classes or phyla or whatever if we want to assess organismal diversity. We must recur to clades and branch lengths for that matter (Daniel Faith works on this).

We'd be much better without Linnaean ranks. They don't add much nowadays and are positively misleading.

Ritchie, curious and a bit kooky how the video link concludes with talking about abortion, killing of abortion doctors, eating meat, etc.

And the examples of subspecies of salamanders and sea gulls shows... common descent of all man? Seriously?

Funny the ring stopped where it did... why didn't they keep going with the video and show the next species out? Because it doesn't exist. So salamanders are still salamanders and gulls are still gulls.

An interesting study worth researching would be regarding the interbreeding of all the ring species. I suspect that even the ones that are not observed to interbreed would have no problem breeding through artifical means. Not that it makes much difference, the biggest problem is that they stopped with the ring species and then went into a bizarre and kind of spooky tangent in their conclusion.

Paul said, "Yet, the patterns in the fossil record provide evidence of a bottom-up process, not a top-down one."

No. The fossil record is does not support gradualism. Have you considered the Cambrian Explosion? It is not unique.

Have you considered that the Cambrian 'explosion' actually took between 10 and 50 million years, depending on your starting/ending criteria? That's at least 100X longer than anatomically modern humans have been on the planet.

You said, "Variation within limits is exactly what we would expect to see over our short life spans. "

That's a convenient plea, but is it does not hold up to the evidence. Species with short life spans and large populations have been studied for years and bacteria are still bacteria, fruit flies are still fruit flies. You have no solid evidence for your statements.

...and mammals are still mammals, vertebrates are still vertebrates.

The fat-headed pastor still thinks evolution means a koala should evolve into a turnip while he watches.

An interesting study worth researching would be regarding the interbreeding of all the ring species. I suspect that even the ones that are not observed to interbreed would have no problem breeding through artifical means.

Strangely enough Tedford studies like that have already been done

STRONG SELECTION AGAINST HYBRIDS AT A HYBRID ZONE IN THE ENSATINA RING SPECIES COMPLEX AND ITS EVOLUTINARY IMPLICATIONSAlexandrino et alEvolution, Volume 59, Issue 6, pages 1334–1347, June 2005

Abstract: The analysis of interactions between lineages at varying levels of genetic divergence can provide into the process of speiation through the accumulation of incompatiable mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders E. eschscholtzii xanthoptica and E. eschscholtzii platensis hybridize in the central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was resampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (1) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730 m to 2000 m; (2) cline centers at the northern Calveras transect were coincident between 1981 and 2001, demonstrating repeatability over five generations; (3) there were very few if any putative F1S, but a relatively high number of backcrossed individuals in the central portion of transects; and (4) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit showed maximum values near the center of the zones. Using estimates of cline width and dispersal, we infer strong selection against hybrids. This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent selection and reinforces the value of Ensatina as a system for the study of divergence and speciation at multiple stages.

They found that while the hybrids at the divergence zones were still interfertile (for now), they had a much lower evolutionary fitness and lower chance of survival. The data clearly indicates a speciation event in the making.

Geoxus:"No way to know. The number of phyla actually depends on complex historical factors"

Sure - my point was simply that there is substantial conservation of body plan, for which phylum is a useful taxonomic reference level. I did not mean to imply any more certainty in Linnaean taxonomic ranks than is warranted and I apologise for being casual in my language!

"We must recur to clades and branch lengths for that matter "

Of course, I agree that referring to lineages and their discontinuities is more accurate than referring to species (or other taxonomic ranks). Species are arbitrary constructs, although I wouldn't say that they are without their uses.

"We'd be much better without Linnaean ranks. They don't add much nowadays and are positively misleading."

Without a better framework, I disagree. While there are subjective aspects in delineating Linnaean ranks, they still serve a purpose.

An example: for those workers investigating global patterns of species richness such as the latitudinal diversity gradient, there is no current robust alternative to the ranks of genera, species and subspecies that are used to delineate biodiversity.

Certainly, molecular diversity is used frequently in such analyses - but not alone. Often it is how this diversity is distributed through comparable units across latitude that is of interest.

Those units of comparison are most typically species, or sometimes genera or families. Provided there isn't a substantial latitudinal bias in how such ranks are defined (actually there is at least some bias) then the ranks are useful.

Neal Tedford " I suspect that even the [salamanders] that are not observed to interbreed would have no problem breeding through artifical means."

It took a second reading before I realized the significance of this statement. Neal is doing something he may never have done on this blog before: Make a prediction. A real ID prediction. Not a retrodiction, or straw man prediction like "If evolution were true, I should be able to watch e. coli turn into monkeys."

Neal, have I understood you correctly? Are you actually saying "If creation is true, then the species at the end of the ring should still be able to interbreed?"

If not, what is your explanation for why they can't? (and remember 'sin' isn't an accepted explanation in biology.)

Derick, the Cambrian Explosion was too short for evolutionists. It strikes a mighty blow to gradualism. Darwin had problems with it and the situation is even worse for evolutionists today because their Darwinian plea that the fossils just haven't been found comes up tired and short.

Darwin predicted, "if the theory be true, it is indisputable that before the lowest Cambrianstratum was deposited, long periods elapsed, as long as, or probably far longer than, the whole interval from the Cambrian age to the present day; and that during these vast, yet quite unknown periods of time, the world swarmed with living creatures."

In the Ediacaran record we find 3 or 4 animal types, in the Cambrian we see about 28 phyla represented within less than 5 million years according to radiometric dating of the strata. We see a wonderful example of top down design, with some variation following.

Derick, the Cambrian Explosion was too short for evolutionists. It strikes a mighty blow to gradualism. Darwin had problems with it and the situation is even worse for evolutionists today because their Darwinian plea that the fossils just haven't been found comes up tired and short.

In the Ediacaran record we find 3 or 4 animal types, in the Cambrian we see about 28 phyla represented within less than 5 million years according to radiometric dating of the strata. We see a wonderful example of top down design, with some variation following.

Funny you should mention that Tedford. Science just found the earliest known hard-shelled fossils dating back 750 million years.

Well, that's simply not true. I'll assume you mean 'not claimed by anyone here recently'. If species aren't fixed, how malleable are they? Can one species split into two completely separate species?

Neal: "No predictions about breeding capability, just a curiosity."

In hindsight, it was pretty silly of me to think your side would actually make a prediction.

Neal: "Limits to change clearly observed since the story line always stops short."

The story line always stops at THE PRESENT CONDITION OF THINGS, dimbulb. You realize that what you're asking is for us to show you what the populations of salamanders or warblers will look like in the future. When talking about the history of life, the story always 'stops' at the present; otherwise it's not history anymore. Why this is so far above your head is beyond me. You are presented with an example of speciation in progress, and your response is that it isn't valid since it hasn't finished yet. When you're presented with speciation events that have finished, you simply deny that the organisms had a common ancestor in the first place. Amazing.

It's really quite simple. A few million years is clearly way too short a time for evolution to work, therefore the cambrian explosion is evidence against evolution.

Also 150 years is clearly way too long a time for evolution not to work, therefore the fact that we haven't seen (m)any speciation events since the publication of On The Origin of Species is evidence against evolution.

It's really quite simple. A few million years is clearly way too short a time for evolution to work, therefore the cambrian explosion is evidence against evolution.

Also 150 years is clearly way too long a time for evolution not to work, therefore the fact that we haven't seen (m)any speciation events since the publication of On The Origin of Species is evidence against evolution.

You said the amount of variation we find in a species' gene pool is 'limited'. Limited by what? How do we identify these 'limits'?

Ring species show us that these 'limits' are not so narrow as to stop one species becoming two. Do these 'limits' prevent one genera becoming two? One family becoming two? One order becoming two?

And how does Creationism explain ring species?

"Funny the ring stopped where it did... why didn't they keep going with the video and show the next species out? Because it doesn't exist."

Pardon? What do you mean 'next species out?' Did you understand the video at all?

"So salamanders are still salamanders and gulls are still gulls."

Yes. But different species of salamanders. Just as humans and chimpanzees are different species of ape.

Venture Free -

"A few million years is clearly way too short a time for evolution to work, therefore the cambrian explosion is evidence against evolution."

??? Too short a time for evolution to work? Evolution works all the time. It is still working now. What a curious thing to say.

What I suspect you mean is that it is too short a time for the process of evolution to transform the first blob of life to the complex creatures which appear from the Cambrian Exlposion. But no-one is making such a claim.

The Cambrian Explosion lasted for around 15 million years, but life itself had been around long before that. Just in small, soft, squishy forms which almost never fossilize. What we see at the Cambrian Explosion is the emergence of 'hard parts', teeth, armour - things which fossilize. The 'explosion' is one in our fossil record, not of life on Earth.

"Also 150 years is clearly way too long a time for evolution not to work, therefore the fact that we haven't seen (m)any speciation events since the publication of On The Origin of Species is evidence against evolution."

Absolute twaddle. Speciation has been observed plenty of times, both in the lab and in the wild - and exactly as much as we should reasonably expect in 150 years.

Obviously, it would be most noticable among small creatures with extremely short lives - such as viruses. Ever heard of viruses or bacteria which become immune to certain drugs? That is because they have EVOLVED a resistance to them. Drug-resistant viruses are a beautiful example of evolution in action. And there are MANY examples of this to be found, I assure you.

Again, I assume what you really mean is 'We haven't seen any large, distinct species [the sort which take millions of years to evolve] appear over the last 150 years, therefore evolution is false.'

Ritchie, I believe Venture Free was pointing out the absurdity of Neal's ramblings.

Poe's law though. I've also not picked up on such sarcasm before, which is a testament to the paucity of Neal's position; It's often very difficult tell if someone genuinely agrees with him, or is mocking him.

It doesn't. In fact, it's goal is to replace explanations with "theistic understandings."

God can't be explained. And since Neal interprets the Bible as divinely revealing that God created human beings in final form, then there can be no explanation.

The Wedge Document makes this goal crystal clear…

Governing Goals

- To defeat scientific materialism and its destructive moral, cultural and political legacies.- To replace materialistic explanations with the theistic understanding that nature and hurnan beings are created by God.

So, Neal won't be providing any explanations. Rather, he'll throw anything he can find at any and all explanations in hope that anything sticks. There just happens to be no other explanations for Neal to focus on. If there were, Neal would be slinging mud at them as well.

In fact, the frequency and force in which creationists attack evolution is a reflection of it's explanatory power.

If evolution was nothing more than just so stories, then why does this blog exist?

I disagree. When we talk about phyla as body plans we imply that those body plans are somehow equivalent. Are we so sure about that? What is so fundamentally different between tardigrades and arthropods, so that they deserve to have separate phyla whereas bivalves and cephalopods are simply classes of Mollusca?

Without a better framework, I disagree.

A framework for what, exactly? They're at least superfluous for classification.

While there are subjective aspects in delineating Linnaean ranks, they still serve a purpose.

Ranks are not delineated. Taxa (or taxon names, depending on how you define "taxon") are delineated. Ranks are simply applied to taxa.

An example: for those workers investigating global patterns of species richness such as the latitudinal diversity gradient, there is no current robust alternative to the ranks of genera, species and subspecies that are used to delineate biodiversity.

I know there are many cases with pretty good correlation between species richness and the richness of families or genera, but I didn't knew taxonomic surrogacy (aka sufficiency) was considered to be robust. As far as I knew (not that I know very much about those methods), the relationship was fairly variable.

It's not your fault that sincere Creationism is indistinguishable from parody. VF's gotten me before too.

I generally tend to be a very sarcastic person, which translates into a whole lot of Poe online. I try really hard to make statements so patently absurd that they can only be understood as parody, but as Poe's law states that's almost impossible.

The truly sad part isn't when I get attacked for making such absurd statements, which I can understand given the basic absurdity of the position I'm mocking. No, the truly sad part is when someone starts praising me for making such a strong argument. To the credit of Darwin's God regulars I don't think that's happened here (at least not that I can remember), but it's certainly happened elsewhere.

You're operating under the assumption that Neal actually has some sort of cohesive, alternative explanation for ring species - or that he actually is seeking an explanation at all.

While it might appear that Neal's objection is to evolutionary theory in particular, this is a misconception which is commonly presented by creationists. In reality, Neal objects to explanations for the biological complexity we observe in any form.

As such, It's unclear why Neal would present an alternative when his goal is to attack any and all explanations.

Looks like I'm not the only one who took a vacation! Hope everyone is able to enjoy the summer weather and take in some of the beauty of God's creation.

Cambrian Explosion.

Estimated length varies, however, the "explosion" is very real.

"Explosion" and the evolutionary necessity/ predictions of "gradualism" are plain contradictions. Will our evolutionist friends here attempt another round of redefining word definitions? A gradual explosion of Junk-Yard Junk-DNA? A slow fuse?

Some evolutionists say that the numbers of phyla, classes, orders, families, and genera all reached or approached their Cambrian peaks during a period of about 5 million years or even less. Some say 5-10 million. Some say 20-40 million. I don't think that anyone can honestly say that the fossil record or the pre-cambrian record is far from complete. A good fossil record exists and the fossils showing a gradual evolution of the 28 phyla is missing from that record.

Taken at face value it is a serious problem to evolutionary claims, but for a theory that doesn't really need evidence, does it really matter one way or another? Any finding can be shoehorned into the theory of evolution.

"Explosion" and the evolutionary necessity/ predictions of "gradualism" are plain contradictions.

Except the "explosion" took tens of millions of years, and the rate of evolution is not necessarily "gradualism". The rate of evolution depends on the environment. Rapid evolution and rapid expansion into new ecological niches is a well documented phenomenon.

"A classic example of ring species is the Larus gulls' circumpolar species "ring". The range of these gulls forms a ring around the North Pole, which is not normally transited by individual gulls.

The Herring Gull L. argentatus, which lives primarily in Great Britain and Ireland, can hybridize with the American Herring Gull L. smithsonianus, (living in North America), which can also hybridize with the Vega or East Siberian Herring Gull L. vegae, the western subspecies of which, Birula's Gull L. vegae birulai, can hybridize with Heuglin's gull L. heuglini, which in turn can hybridize with the Siberian Lesser Black-backed Gull L. fuscus. All four of these live across the north of Siberia. The last is the eastern representative of the Lesser Black-backed Gulls back in north-western Europe, including Great Britain.

The Lesser Black-backed Gulls and Herring Gulls are sufficiently different that they do not NORMALLY hybridize; thus the group of gulls forms a continuum except where the two lineages meet in Europe.

However, a recent genetic study entitled The herring gull complex is not a ring species has shown that this example is far more complicated than presented here (Liebers et al., 2004" Wikipedia Ring species.

Apparently they can hybridize, but don't NORMALLY do so.

So what assumptions need to be made for this to show univeral common descent?

"The Ensatina salamander has been described as a ring species in the mountains surrounding the Californian Central Valley. The complex forms a horseshoe shape around the mountains, and though interbreeding can happen between each of the 19 populations around the horseshoe, the Ensatina eschscholtzii subspecies on the western end of the horseshoe cannot interbreed with the Ensatina klauberi on the eastern end. As such it is thought to be an example of incipient speciation, and provides an illustration of "nearly all stages in a speciation process" (Dobzhansky,1958)." Wikipedia Ensatina

This is probably the most interesting of the ring species, however, they remain subspecies. Perhaps if the species borders and distinctions become clearer in the ensatina many years from now, biologists might split them into more than one species. Time will tell.

One explanation that comes to mind is the possibility that the ring arraingment developed after the ancestral individuals were created. One type of salamander was created. The different sub-species evolved afterwards.

Another explanation is that every species shows interaspecies variation. Some species show preferential mating habits. This takes different forms in different species. In the case of the ring species, the variation is geographic.

One explanation that comes to mind is the possibility that the ring arraingment developed after the ancestral individuals were created. One type of salamander was created. The different sub-species evolved afterwards.

Then what's the ID explanation for the markedly lower evolutionary fitness between hybrid crosses along the boundaries of the different subspecies? Are you now agreeing that evolution can result in the formation of new species?

natschuster, it is interesting that the ring species remain subspecies according to taxomonists. How is this even real speciation then? Regardless of fussing over the rather ambiguous definition of species, this is another evolutionary attempt to try to squeeze a big conclusion from a small observation.

Creationists, for as long as I know, have not maintained fixity of species and have said all along that variation with limits occurs. So ring species have not even risen above the level of a subspecies that I know of, so this is interesting, but not a big deal.

Examples of canines, felines, ligers, tigons, wolphins, leopons, pizzly bears, camas, zorses, and plant hybrids suggest a possible ancestry for various families of animals and plants. Variation within limits is all we ever observe, and gradualism at all levels is not what the fossil record shows. So evolutionists are again a dollar short.

natschuster, it is interesting that the ring species remain subspecies according to taxomonists. How is this even real speciation then? Regardless of fussing over the rather ambiguous definition of species, this is another evolutionary attempt to try to squeeze a big conclusion from a small observation.

The big conclusion doesn't come just from this small observation, Idiot. This small observation is one of millions of consilient and corroborating observations that taken as a whole support the big conclusion.

Natschuster has admitted that processes leading to speciation are real. What is your explanation for ring species Tedford?

I would venture to say that the original Ensatina was designed whereever an evolutionist would say it evolved.

Yep, you'd say that, but only because that's what your religious training taught you. Sadly for that view, there is not one iota of scientific evidence to support the 'design' idea and tons that support the 'evolved' idea.

Quote from NY Times - "The push right now is developing “flapping wing” technology, or recreating the physics of natural flight, but with a focus on insects rather than birds. Birds have complex muscles that move their wings, making it difficult to copy their aerodynamics. Designing insects is hard, too, but their wing motions are simpler. “It’s a lot easier problem,” Dr. Parker said. "

Gee Tedford, that's really amazing. To produce micro-miniature air vehicles, scientists are studying creatures that have had 300 million years of evolutionary history to optimize the physical mechanisms.

I bet you're astounded every time you open the refrigerator and the little light in the back comes on too, right?

It rather seems to me that you have missed the point of ring species. Speciation does not ONLY happen around geograhpical features. A species may live in the same habitat and still form two sub-groups. In such cases, the difference between them initially will be little more than preference. Eventually differences will become apparent, even while they are still capable of hybridization. Lions and tigers once shared a habitat. And they are physically capable of successfully cross-breeding. Yet do we have any trouble of distinguishing them as seperate species?

Though Lesser Black-backed Gulls and Herring Gulls may be capable of hybridizing, that does not make them the same species any more than it makes horses and donkeys the same species, or lions and tigers.

"This is probably the most interesting of the ring species, however, they remain subspecies."

?? The salamanders at the southern tip of the Great Rift Valley are not subspecies. They are distinct species. And we would have no trouble in classing them as such, were it not for the curious fact of a chain of subspecies connecting them around the valley. This is what makes them a ring species.

" it is interesting that the ring species remain subspecies according to taxomonists. How is this even real speciation then?"

How would you like taxonomists to class them? The cretures a quater, or halfway along the chain are just as imortant as the ones at the ends, yet make no mistake that the species at either end of the chain are distinctly seperate enough to be counted as seperate species, were it not for the intermediaries. That's the whole point.

This is exactly the sort of ambivalence and taxonomical problem we would expect if speciation does indeed occur through evolution. Conversely, it does not fit with the neat taxonomy implied by the mantra 'gulls always give rise to gulls'. This implies a fixity of species which ring species belie.

"Creationists, for as long as I know, have not maintained fixity of species and have said all along that variation with limits occurs."

Yeah, it's the 'limits' that I'm taking issue with. What are these limits? Where are these limits? I want to talk limits. My whole point of bringing up ring species was to demonstrate that these alleged limits do not prevent speciation. They do not stop one species becoming two. So where are they to be found? If variation can produce two species from one (which ring species are a dramatic demonstration of), why not two genera from one, or two orders from one?

One explanation that comes to mind is the possibility that the ring arraingment developed after the ancestral individuals were created. One type of salamander was created. The different sub-species evolved afterwards.

Another explanation is that every species shows interaspecies variation. Some species show preferential mating habits. This takes different forms in different species. In the case of the ring species, the variation is geographic.

One thing that immediately strikes me about these explanations is that neither of them logically follow from ID.

Applying the "rules" of evolution to a specific type of geography leads logically and inevitably to ring species. That is to say if evolution is true, then ring species are a necessary result of the evolutionary process. This of course doesn't prove that evolution is true, but the fact that we actually observe in nature what is a necessary outcome of evolution theory gives strong support for the theory. Evolution "explains" ring species.

The same cannot be said of ID. The ring arrangement may have developed after ancestral individuals were created. However this is not a necessary result of the application of the "rules" of ID. The ring arrangement may simply be one choice among many as far as intraspecies variations go. Again, this is not a necessary result of the application of the rules of ID. There are a multitude of possible explanations for ring species, none of which are logical necessity according to ID. This of course doesn't prove that ID is false, but it is a case where an observation provides strong support for one theory, but provides no support whatsoever for another. ID does not "explain" ring species.

If you are going to replace an existing theory, the new theory should explain everything that the current theory explains as well as some things that it doesn't. Evolution clearly explains the existence of ring species. ID clearly does not.

Nat: All we can say for sure is that processes that lead to intraspecies variation exist.

Nat, do you realize you've just presented an claim which is clearly a variant of solipsism?

Specifically, solipsism makes the claim that "all I can say for sure is that I exist." Beyond that, there may not be a external reality. What appears to be "other people" may actually be highly elaborate zombies that merely appear to be conscious. They exist, but merely as facets of my internal self.

While you might think you've retreated to a position which is somehow free from objective criticism, this not the case. The connection clear. You're making exactly the same appeal. You've just arbitrarily moved boundary from one's mind to intra-species variation.

However, I'm guessing you're just stating the party line by repeating an argument you've heard elsewhere. In fact, despite having it pointed out to you, it's likely that you still won't see the connection.

And if you do see the connection, you'll probably will feign ignorance because you have no other alternative. I suspect that Cornelius is versed enough in philosophy to recognize his argument is a variant of solipsism when it's spelled out for him. However, this would only indicate God has made the path of the righteous more difficult to travel. He must preserver at all costs.

My understanding is that solipsism is he belief that one's internal reality is the only reality. We aren't talking about internal reality. We are talking about an external fact, namely that species can develop intra-species variation. The question is whether we can extrapolate, species-to-species change from intraspecies variation. Maybe it can only go so far. I know I can jump three feet. So if I can jump three feet, I know I can jump thirty feet, by extrapolation. Saying that I can't infer thirty feet from three feet isn't solipsism.

"The question is whether we can extrapolate, species-to-species change from intraspecies variation."

Ring species are not merely an example of intraspecies variation. The species at either end of the chain are seperate enough to count as distinct species, were it not for the curious existence of the intermediates linking them. They may still be able, occasionally, to hybridise, but then so can lions and tigers, or horses and donkeys. Are lions and tigers just examples of intraspecies variation within a single species? Or are they, in fact, seperate species?

"Maybe it can only go so far. I know I can jump three feet. So if I can jump three feet, I know I can jump thirty feet, by extrapolation."

There are, of course, limiting factors to how high you can jump - how big your muscles can grow, how much force is required to lift you that high off the ground, etc. What are the factors which limit how much a species can vary?

natschuster: My understanding is that solipsism is he belief that one's internal reality is the only reality.

It's not really a belief, per se. It's an argument based on the assumption that I can only know for certain that I exist.

I can't be 100% certain you merely appear to be conscious because I can't actually experience things from your perspective. Appearances can be deceptive. You might be an elaborate zombie that only appears to be conscious.

As such, the argument that the only reality is ons'e internal reality is based on a limitation of what we supposedly cannot know. Essentially, solipsism says we cannot explain why people appear to be conscious. It's beyond human reasoning and problem solving.

You're making a variation of the same argument. Instead of the boundary being draw at our minds, you've drawn it at an explanation for speciation.

natschuster: "Maybe it can only go so far. I know I can jump three feet. So if I can jump three feet, I know I can jump thirty feet, by extrapolation. Saying that I can't infer thirty feet from three feet isn't solipsism."

So, with one jump you can cover a distance of 3 feet? Do that 10 times in a row in one direction, then measure how far you've gone.

If they look a lot alike, and can hybridize, and doi experience genetic mixing, through the geographic intermidiates, then maybe they are one species.

And some limiting factors to speciation might be they number of mutations needed, the time frame, the fact that some adaptive mutations are a trade off, there might be some bad side effects that can accumulate.

"If they look a lot alike, and can hybridize, and doi experience genetic mixing, through the geographic intermidiates, then maybe they are one species."

So you have arrived at the conclusion that lions and tigers belong to the same species? That horses and donkeys are the same species too? Your argument has led you to an absurdity. This is a sign that your argument is flawed. Please take time to consider how this might be.

"And some limiting factors to speciation might be they number of mutations needed, the time frame, the fact that some adaptive mutations are a trade off, there might be some bad side effects that can accumulate."

You are speculating. Can you demonstrate, or point me to someone who can demonstrat,e that we have reason to think any of these might actually be the case?

If they look a lot alike, and can hybridize, and doi experience genetic mixing, through the geographic intermidiates, then maybe they are one species.

What if we empirically observe a process changing them so they can't hybridize and don't experience genetic mixing? What magic barrier would stop the process before speciation is complete?

And some limiting factors to speciation might be they number of mutations needed, the time frame, the fact that some adaptive mutations are a trade off, there might be some bad side effects that can accumulate.

And monkeys might fly out of your butt the next time you type. Do you have any evidence for your hypothesized barriers that would preclude speciation?

It hasn't been established that I can jump ten times

We see you jump 3', and we find track marks that indicate someone in the past jumped 10 times in a row for a 30' total.

Horses and donkeys look different, and their hybrids are usually sterile. And they don't have mixing of genes through the intermediate subspecies.

And people are studying mutations rates, and time constraints. A recent study estimated that it would take 100,000,000 years for a adaptation that reuires only two mutations to work its way through a population that reproduces at the rate humans do. And a recent study indincates that the increase in fitness diminishes with each subsequent mutation.

"Horses and donkeys look different, and their hybrids are usually sterile. And they don't have mixing of genes through the intermediate subspecies."

Very good! That is true. Genes from horse and donkey populations do not, in fact, mix because mules are sterile, and therefore these hybrids are always the end of their genetic line. However, this is true of my above examples of the salamanders, finches and gulls. Though they can hybridize, a species from one end of this ring species chain really is genetically different and incompatible enough to be marked as a seperate species from the one at the other end of its chain.

"A recent study estimated that it would take 100,000,000 years for a adaptation that reuires only two mutations to work its way through a population that reproduces at the rate humans do."

Could you source this please?

Though without even looking at it, allow me to point out that from a gene's point of view, humans are incredibly large and long-living creatures who consequently evolve very slowly.

"And a recent study indincates that the increase in fitness diminishes with each subsequent mutation."

Could you source this too please. I'm not even really sure what you mean by it.

Horses and donkeys look different, and their hybrids are usually sterile. And they don't have mixing of genes through the intermediate subspecies.

Lions and tigers look different, their hybrids are fertile, and they do occasionally mix genes. Why aren't they one species?

And people are studying mutations rates, and time constraints. A recent study estimated that it would take 100,000,000 years for a adaptation that reuires only two mutations to work its way through a population that reproduces at the rate humans do.

Here's the one where Tedford the Idiot and the rest of the mouth breathers at UD misread and misrepresented the paper. That includes having the author of the paper himself email them to tell them they were full of it.

In case it's not clear, Nat is appealing to the fact that that we cannot go back in time and observe speciation. This is the same sort of objection made when Solipsists point out I cannot experience things from someone else's perspective to determine they too are conscious.

Furthermore, as many have pointed out here, ID doesn't explain speciation. Just as solipsism doesn't explain why object-like facets of my internal self would behave laws of physics-like facets of my internal self.

Both present convoluted elaborations of modern evolutionary synthesis and Realism, respectively.

Nat: I'm suggesting that it doesn't necessarily follow that the evolution of ring sub-species means that one species can evolve into another.

Your claim has additional implications, whether you're aware of them or not. Are you abandoning your earlier claims? Specifically…

Nat: The evolutionary explanation for the reduced fitness, whatever it is, will work just as well for the first ID explanation I provided.

Nat: All we can say for sure is that processes that lead to intraspecies variation exist.

If all we had were observations of abstract variation between organisms over a finite geological ring, then yes I'd agree. However, this is is merely a drop in the bucket.

To return to Solipsism, we explain isolated and individual responses from other people's behavior with the theory that other people actually are conscious, in reality. We do this despite the fact that the conclusion (people actually are conscious, in reality) does not necessarily follow from individual aspects of other people's behavior if evaluated merely in isolation.

In other words, it's the overwhelmingly combined responses across multiple scenarios, individuals, etc which leads us to our conclusion. Furthermore, Solipsism provides no explanation as to why concuss being-like facets of my internal-self would surprise me, disagree with me on Solipsism and even discover new laws of physics-like facets of my internal self that I wasn't aware of. Nor can I do the math necessary to understand them fully. Why do object-like facets of my internal self follow these laws of physics like facets?

That's just what my internal self happened to project.

In the same way, ID doesn't actually explain subspecies variation or species variation for that matter. For example, how does the evolution of subspecies variation fit into the designer's big picture? Why are small changes left to natural cause while speciation changes are by design only. What prevents subspecies changes from becoming speciation events? Why do changes between species show very specific constraints that are completely unnecessary for an abstract designer that has no limits?

That's just what the designer must have wanted.

Again, Solipsism and ID in it's current form represent convolved elaborations of the prevailing explanations of realism and modern evolutionary synthesis.

I didn't say above fitness decreases. I said the increse in fitness diminishes. That means that it will eventually reach zero, and then there will be no more increasing fitness to drive evolution.

So in a completely unchanging environment evolution will work to asymptotically approach the local fitness peak. Once you reach the top there's nowhere left to climb, right?

How often in the real world do you find a completely unchanging environment nat?

And here's the study on time frames:

http://www.genetics.org/content/180/3/1501.full

Once again I see you were too lazy to actually read the paper or understand what it says. As always, you're satisfied regurgitating crap from the IDiots at the DI or UD. The paper doesn't say what you claim

"natschuster: "A recent study estimated that it would take 100,000,000 years for a adaptation that reuires only two mutations to work its way through a population that reproduces at the rate humans do. "

The paper showed it would take that long for a very specific sequence of a coordinated pair of mutations that first inactivates a binding site and then creates a new one. It also says

"Fortunately, in biological reality, the match of a regulatory protein to the target sequence does not have to be exact for binding to occur. Biological reality is complicated, with the acceptable sequences for binding described by position weight matrices that indicate the flexibility at different points in the sequence. To simplify, we assume that binding will occur to any eight-letter word that has seven letters in common with the target word. If we do this, then the mean waiting time reduces to ∼60,000 years."

and

"In addition, we use these results to expose flaws in some of Michael Behe's arguments concerning mathematical limits to Darwinian evolution."

Once again your ignorance and laziness has hung you out to dry. Don't you ever get tired of embarrassing yourself this way?

Geoxus:"Sigh... I won't even try it. Hate to say this, Paul, but I told you so... "

Haha, for sure. Point taken - but I shall take no responsibility for the misuse of ideas by creationists ;)

Sorry I haven't replied to your other post - things have been rather hectic of late. To reply in brief, I think that while we might have been mildly at cross-purposes earlier, on further reflection I agree with you.

Even in the applications where Linnaean taxonomy is useful, it isn't necessary. And, yes, at worst, it is a kind of misleading shorthand that, in the broader scheme, isn't and perhaps *can't* be coherent.

...but I shall take no responsibility for the misuse of ideas by creationists ;)

Of course Tedford doesn't care about misrepresenting anyone, but do I think biologists have certainly been sloppy communicators in this regard, and, even worse than that, many actually reify taxonomic categories (*cough* GG Simpson *cough*).

Thoron: We've asked you and Tedford the Idiot and every other Creationist who makes that same dumb claim the same question, and never gotten an answer. NEVER

They usually either fail to respond or try to change the subject - only to repeat the very same claim not long after while commenting on another post. And they do so as if this discussion never happened.

We eventually ask the question again, and the cycle repeats itself.

Clearly, they're merely throwing anything they can find, even the same tired arguments, hoping that it sticks. Perhaps they think God gives out 'A's for effort?

The funny thing is, anyone can verify this by simply looking though the comments on previous posts. It's all here in black and white.

The paper on diminishing fitness returns does establish that the concpet exists. The way around it is to change the environment in a different way, which means evolution will proceed in a different direction, but it will run up against the same wall. So it seems that evolution can only proceed so far in any direction. That's kinda what I've been saying.

And the authors paper on time constraints got around the problem by making assumptions about a specific case. Maybe those assumptions are wrong, or don't apply to other cases. Anyway, time constraints are a problem.

By the way do we know how many mutations it takes to turn one species into another? Maybe it requires so many that there just isn't enough time. I know I'm speculating here, but I think it is an important question.

The paper on diminishing fitness returns does establish that the concpet exists. The way around it is to change the environment in a different way, which means evolution will proceed in a different direction, but it will run up against the same wall. So it seems that evolution can only proceed so far in any direction. That's kinda what I've been saying.

When and for how long does an environment stay completely unchanging nat?

And the authors paper on time constraints got around the problem by making assumptions about a specific case. Maybe those assumptions are wrong, or don't apply to other cases. Anyway, time constraints are a problem.

They're only a problem to creationist trolls who didn't read the paper and don't understand the concepts.

By the way do we know how many mutations it takes to turn one species into another? Maybe it requires so many that there just isn't enough time. I know I'm speculating here, but I think it is an important question.

No, you're not speculating. You're trolling because you've already brought up this stupidity and been answered at least three times now.

Whether in plants or animals the variation never radiates far from the original ancestor. For UCD to be valid we would have observed much more plasticity in life forms. Simply stated, dogs are still dogs, fruit flies are still fruit flies, e-coli is still e-coli, corn is still corn, and tomatoes are still tomatoes, etc. A billion generations and a billion years won't fundamentally change them beyond some variation.

Neal Tedford: "Simply stated, dogs are still dogs, fruit flies are still fruit flies, e-coli is still e-coli, corn is still corn, and tomatoes are still tomatoes, etc. A billion generations and a billion years won't fundamentally change them beyond some variation."

... And even if you could prove UCD, that wouldn't mean organisms 'change over time': mammals are still mammals, chordates are still chordates, and eukaryotes are still eukaryotes. No change. Still the same basic 'kinds'.

Whether in plants or animals the variation never radiates far from the original ancestor.

Hey idiot, please give us your explanation for the Hawaiian silversword alliance, a family of over 50 plants of vastly differing morphologies that genetic analysis shows all arose from a single immigrant species to the islands

For UCD to be valid we would have observed much more plasticity in life forms.

We do. Oh, that's right. The fat-headed pastor demands we see millions of years' worth in a few months in the lab.

Simply stated, dogs are still dogs, fruit flies are still fruit flies, e-coli is still e-coli, corn is still corn, and tomatoes are still tomatoes, etc.

The dogs we have today didn't exist 20,000 years ago idiot. Modern dogs are descended from gray wolves that lived in the middle east. Same for corn. Modern corn didn't exist 10,000 years ago. Early maize which evolved into modern corn is a domesticated form of wild teosinte.

A billion generations and a billion years won't fundamentally change them beyond some variation.

Except it already has you idiot, and we have the evidence to support it.

But it will evolve in a new direction, and it will be limited in how far it can evolve.

So? Every time the environment changes that limit gets moved to a new spot leaving room for more evolutionary change. Evolution goes towards the limit but never gets there because the limit keep moving too.

nat, you were very interested in the number of mutations required for speciation. You where shown examples that require a single mutation, and I mentioned an example of speciation that depended on a single gene. You said this was very important. What is the conclusion?

Nat, how are you coming with that list of assumptions and problems in the papers you cited?

I'll ask the same question Geo did. Why is it that when you thought the papers supported Creationism they were golden, but soon as you found out the papers actually said the exact opposite of what you thought suddenly they were full of bad assumptions?

natschuster: "Corn can't survie by itself. I meant to say bad for the corn. My bad So all that demonstrates at most is that the a mutation can bring about a nerw species is detrimental "

Yeah, that's why corn went extinct 10,000 years ago. (?!?!)

That's one of the dumbest things I've heard on this blog yet. (whenever I think I've heard the dumbest thing that can be said by a creationist, I am usually proved wrong within the month.)

Nat, you've been in rare form recently. Salvage what's left of your dignity and stop talking for a while. Think things through before you post. Read articles before you offer them up as evidence for your position, especially ones that refute your position.

Fortunately, in biological reality, the match of a regulatory protein to the target sequence does not have to be exact for binding to occur. Biological reality is complicated, with the acceptable sequences for binding described by position weight matrices that indicate the flexibility at different points in the sequence. To simplify, we assume that binding will occur to any eight-letter word that has seven letters in common with the target word. If we do this, then the mean waiting time reduces to ∼60,000 years.

And an organism can evolve in one direction only so far. When the environment changes, it changes the direction of evolution. But it can evolve only so far in the new direction. Whne the environment changes again, the organism will evolve in new direction but only so far.

Thorton: "I'll ask the same question Geo did. Why is it that when you thought the papers supported Creationism they were golden, but soon as you found out the papers actually said the exact opposite of what you thought suddenly they were full of bad assumptions?"

If it wasn't for people planting corn, it couldn't exist. This means that the mutation would prove fatal for the corn if humans didn't intervene. This means that this process wouldn't lead to speciation without people, but rather extinction.

I understand that the single gene mutation in the snail changes the direction of the spiral which makes mating difficult.

Wow, you did some research? Bravo!

the reproductive isolation might lead to a new species. Or it might not.

Yes, it might happen. It can happen. It has happened. It happened at least three times in the Euhadra clade. Again, what's your point?

Thorton:

When and for how long does an environment stay completely unchanging?

Probably nat also fails to get that populations colonise new environments. And that all of this fitness peak discussion deals only with NS. Evolution never gets completely stuck because of genetic drift.

natschuster: So how did all these species evolve to use each other? I'm just asking.

That's not so hard to understand, is it? From plants that originally pollinated by other means, e.g. wind-borne, that are fed upon by insects who happen to carry pollen to other plants. Those plants with flowers that were more attractive to the pollinators would have their pollen dispersed more widely. Similarly with fruit and seed.

Speciation isn't the same as complete reproductive isolation. Lions and tigers are separate species, but can produce viable offspring; nevertheless, they are clearly distinct species. Nor is speciation always a black-and-white phenomenon, but isolation can vary by degree.

The authors say that they simplify things by making an assumption. Has it been established that the assumption is true?

Still waiting for an answer to this first:

Why is it that when you thought the papers supported Creationism they were golden, but soon as you found out the papers actually said the exact opposite of what you thought suddenly they were full of bad assumptions?

If it wasn't for people planting corn, it couldn't exist. This means that the mutation would prove fatal for the corn if humans didn't intervene.

But humans do exist and intervene. Humans are part of corn's environment.

This means that this process wouldn't lead to speciation without people, but rather extinction.

No, it means those particular mutations would have been fatal in a different environment, one with no humans. In their particular environment the mutations were very favorable. The processes that produce speciation still work fine.

And an organism can evolve in one direction only so far. When the environment changes, it changes the direction of evolution. But it can evolve only so far in the new direction. Whne the environment changes again, the organism will evolve in new direction but only so far.

Suppose you have a car that can go "only so far", say 100 miles, on a tank of gas. You start off at home and drive 100 miles. There you find a gas station and refill the tank. You drive off again and only go another 100 miles. There you find another gas station and refill. You go another 100 miles then refill, then another 100 miles and refill, then another 100 miles.

What's the maximum you can be from your original starting point nat, even though your car can go "only so far"?

I mentioned one assumption. All assumptions are suspect. The rst of the paper seems to be based on analysis of the data.

So corn just happened to be lucky. So maybe every mutation that causes speciation will be harmful the same way, unless the organism is as lucky as corn is. So does evolution require this degree of serendipity?

And in yuor car analogy, you are going in one direction. But when the environment changes that will change the direction of evolution. How far will you go if you have to change directions every 100 miles. Adn what happens if the environment changes back? Climate fluctuations, glaciers advancing and retreating, stuff like that. Then the organism will have to go back to its previous state.

I mentioned one assumption. All assumptions are suspect. The rst of the paper seems to be based on analysis of the data.

You keep avoiding the question

Still waiting for an answer to this:

Why is it that when you thought the papers supported Creationism they were golden, but soon as you found out the papers actually said the exact opposite of what you thought suddenly they were full of bad assumptions?

So corn just happened to be lucky. So maybe every mutation that causes speciation will be harmful the same way, unless the organism is as lucky as corn is. So does evolution require this degree of serendipity?

No, not 'lucky'. The mutations that were beneficial were filtered and accumulated via natural selection. Why do Creationists always harp on the "random=lucky" strawman and forget all about the selection part?

And in yuor car analogy, you are going in one direction. But when the environment changes that will change the direction of evolution. How far will you go if you have to change directions every 100 miles.

Change direction doesn't mean reverse direction there squiddy.

You can up to N x 100 miles for N iterations. You'll certainly go more than 100 miles from your starting point, given time and iterations. So much for your 'limit'.

Adn what happens if the environment changes back? Climate fluctuations, glaciers advancing and retreating, stuff like that. Then the organism will have to go back to its previous state

So what if it changes back? Species then are at a completely new starting point than before. It will follow a new path which can resemble an earlier state but certainly doesn't have to.

Sorry squid ink, but as long as the environment is dynamic there will be no fixed limits to evolution variation.

Inthe case of maize, the mutation would have killed it. People happened to be there. Maybe other mutations that cause that sort of change will kill the organism, as well, unless there is something there to rescue it.

And if the organism changes the direction of evolution due to random environmental changes, I do believe that we would see something like a random walk. I do believe that random walks don't get you very far.

Inthe case of maize, the mutation would have killed it. People happened to be there. Maybe other mutations that cause that sort of change will kill the organism, as well, unless there is something there to rescue it.

Some probably will. Others won't - they'll be beneficial. The beneficial ones will tend to accumulate. The effect depends on the environment, like we keep telling you.

And if the organism changes the direction of evolution due to random environmental changes, I do believe that we would see something like a random walk. I do believe that random walks don't get you very far.

I should clarify for the lurkers: In a true random walk the probability of returning to the origin location decreases as the number of dimensions increases. Evolution has millions if not billions of 'dimension' - places that sites on the genome can change. The probability of randomly returning to an original starting genome that has been undergoing evolution is negligible, functionally zero.

I know at least some are inferred, but this kind of isolation seems to happen so easily that I think it's possible that some instances have been observed as well. I'm feeling lazy today, why don't you look it up and tell us?

And how is colonizing a new area any different than changing the environment?

I mentioned it because it's similar, not to make a difference. But if you want to know, you don't have to compete with the ancestral stock of your population in the new environment.

It will lead to evolution in a new direction, but it can only go so far.b

NS alone can only climb to the nearest peak, assuming the environment and the organism-environment relationship (organisms are not passive, they modify their environment) remain constant. Sometimes they can remain so, at a very gross scale. This can explain long stases, like in nautiloids, who live deep down in the water column, in an environment that tends to be perturbed very little. But most of the times, things don't remain the same. Note that the environment includes other organisms.

And if the organism changes the direction of evolution due to random environmental changes, I do believe that we would see something like a random walk. I do believe that random walks don't get you very far.

Do you teach science, nat? According to you the gas diffusion models used by physicists don't work, because the molecules would tend to remain in their initial position. By the way, many people would be quite happy describing the big picture of evolutionary history as something like a random walk. Ever read Stephen Jay Gould? Oh, wait, I know the answer...

natschuster: In the case of maize, the mutation would have killed it. People happened to be there.

Some traits that would be good in a garden would be deselected in the wild. That's the whole point, of course.

In any given population, there are going to be some corn plants with larger ears and some with smaller ears. In a natural environment, there is a limit to how large grains become due to the energy costs. But if humans do the planting, weeding and fertilizing, and select for larger ears, then the ear size can increase.

natschuster: And if the organism changes the direction of evolution due to random environmental changes, I do believe that we would see something like a random walk. I do believe that random walks don't get you very far.

Not sure what you mean by "random environmental changes". The environment is hardly random, and organisms can adapt to diurnal and seasonal cycles. But if you mean, for instance, the amount of rain may vary stochastically from year to year, then organism can adapt to that facet of the environment, as well. Many plants can survive as a species even very long droughts by producing seeds. Just as importantly, they can vary their range as conditions change. You'd have to be more specific to say more.

Has the fact that other people are actually conscious been observed? Or is it inferred?

Specifically, you cannot know for certain that anyone but yourself is conscious because you cannot actually experience things from their perspective. I think, therefore I am. But I do not know that you actually think, therefore I cannot know you "are".

Yet, I'm guessing you do not suggest the existence of this limitation prevents us from explaining why people appear to be conscious.

In the case of evolutionary theory, we cannot go back in time and observe the evolution of life that already exists. Nor can we fast forward to observe the effect of evolution over an extended amount of time. Nor is our current environment the same as it was when evolution occurred in the past.

Yet, you seem to be suggesting that these limitations prevents us from explaining the biological complexity we observe.

Furthermore, on close examination, we note that your objection isn't merely limited evolution's explanation for the biological complexity we observe. Instead, you object to any sort of explanation at all. This is because you either fail to provide alternative explanations or appeal to explanation-less theories presented by the current crop of ID proponents.

So, again, it appears that you're merely throwing anything you can find at any sort of explanation, in hope that it will "stick."

This is also apparent by your quick turn against the very same paper that supposedly "proved" evolution wasn't possible.

I'm a simple gut. I'm not very good with big, metphysical questions. But I'll try.

#1. I guess you're write, I don't really know if people around me are really concious, or even exist. I guess I'm ultimately relying on instinct.

#2. Didn't I provide an ID explanation for ring species? That's how this whole thing started.As to the next question, why would a designer do it that way, well that would be theological question, if the designer is God. If the designer is an ET, then I guess he would be showing off. Humans do things like that. Or maybe the designer wanted to make an interesting world for humans to live in. I'm not a theologian.

#3. I accepted the parts of the paper that were based on research and analysis. I question the part where the authors admit they are making an assumption. Assumptions are suspect.

The question is how different it is from the original species. Can it become different enough to become a new species?

Again, the delimitation of species massively depends on the species concept used. But many modern workers would reject speciation without cladogenesis, so even great anagenetic change would not be considered speciation.

But the answer remains yes.

And wouldn't the scenario we are talking about resemble a multidimensional random walk?

Yes, duh. And that can get you very far, what part of it can't you understand? *headdesk*

natschuster: While it is possible to move really far away in a random walk, probability dictates that the chances of getting really far are limited. Its all about probabilities. Please correct me If I'm wrong.

You're wrong. Though the average distance traveled in a random walk is zero, the standard deviation increases as the square root of the number of steps. If you have a number of random walkers, they will diffuse into the surrounding environment. Like perfume.

This is similar to the misunderstanding by many IDers that conflates a large population over a small number of generations with a small population over a large number of generations. They are not the same.

Consider a camp that sends out a hundred scouts, each traveling and returning in a day. Due to their numbers, they will fully explore the surrounding territory. Now the camp sends out ten scouts, each traveling out, but not returning for ten days. They may not explore every point near the camp, but they will search much farther afield. Nevertheless, both groups take the same number of steps. And if the terrain (fitness landscape) isn't flat, then following the terrain may lead to many new discoveries.

We aren't talking about an unlimited number of walkers. We are talking about one species, that evolves in one direction, then evolves in another as the environment changes. And if we are talking about a large numnber of environmental changes, doesn't that add to the time factor? We have to wait for the environment to change, which happens in geological time, then we have to wait for the organism to evolve. Has anyone ever done the math?

natschuster: We are talking about one species, that evolves in one direction, then evolves in another as the environment changes.

A species is a *population*. This is what you said:

natschuster: While it is possible to move really far away in a random walk, probability dictates that the chances of getting really far are limited. Its all about probabilities. Please correct me If I'm wrong.

Yes, you were wrong. Random walkers will move a distance on the order of sqrt(steps).

natschuster: We have to wait for the environment to change, which happens in geological time, then we have to wait for the organism to evolve.

The environment is always changing; day and night, seasons change, it's different under a rock than on top of the rock. And there's the biosphere itself, always changing.

natschuster: We don't have a whole lot of individuals doing a random walk. WE are talking about one species evolving into another.

This is a standard model.

We have a population. Think of them being on a landscape, which we assume is flat (no biases). If one lineage experiences a mutation, then it is now positioned on a different place on the landscape near the starting point. Over time, the various lineages move across the landscape, with each step being random, a random walk. They will eventually disperse and explore the surrounding area of the landscape. That was the question you asked.

natschuster: Are the changes in the environment that you described the sort that will drive evolution? We need major changes to creat a new fitness peak to start the process over.

As we mentioned above, the environment is not random. Now you're talking about fitness peaks, but that's not random. Went back a bit to find out what you're talking about.

natschuster: The organism doesn't have to return to the origin. The question is how different it is from the original species. Can it become different enough to become a new species?

Even in a completely random walk, populations can significantly diverge from the origin. As for speciation, that usually entails reproductive isolation. You seem to be confusing two different aspects of the process, adaptation/drift with the processes of speciation.

The idea is that populations become isolated, then diverge for one reason (drift) or another (local adaptation), changing enough to become permanently isolated in terms of reproduction. Once this occurs, they will continue to diverge.

The evidenc sited above shows that eventually the increase in fitness with each subsequent mutation in on environment will apporahc zero, so there will be no more fitness increase to drive evolution. What is needed is a change in the environment to create a new direction for evolution to follow, to pursue a new fitness peak. But then the cycle will repeat and the fitness increase will slow down again. The constant change in the direction of evolution in pursuit of a new fitness peak, IMHO, resembles a random walk. But this probably won't get us very far. We are talking about a population evolving into a new species.

The evidenc sited above shows that eventually the increase in fitness with each subsequent mutation in on environment will apporahc zero, so there will be no more fitness increase to drive evolution. What is needed is a change in the environment to create a new direction for evolution to follow, to pursue a new fitness peak.

And in the real world that's exactly what we see. Too bad for the Creationists.

But then the cycle will repeat and the fitness increase will slow down again. The constant change in the direction of evolution in pursuit of a new fitness peak, IMHO, resembles a random walk.

You keep trying to paint the picture of evolution as a 1-dimensional random walk. It's not. If you want to use that model, it's a millions-of-dimensions random walk. The probability of it coming back to the same location is functionally zero.

But this probably won't get us very far. We are talking about a population evolving into a new species.

Your stupid 1-dimensional model won't get very far. But since your stupid model has no connection to reality, it doesn't matter.

natschuster: The evidenc sited above shows that eventually the increase in fitness with each subsequent mutation in on environment will apporahc zero, so there will be no more fitness increase to drive evolution.

There was negative epistasis for most but not all traits. It's rather expected that organisms will cluster around the local fitness peak.

natschuster: What is needed is a change in the environment to create a new direction for evolution to follow, to pursue a new fitness peak.

There are a number of mechanisms to move off of peaks, such as recombination.

natschuster: The constant change in the direction of evolution in pursuit of a new fitness peak, IMHO, resembles a random walk.

No. More like sifting. In any case, you are probably thinking of a two-dimensional fitness landscape, while the actual landscape has many degrees of freedom. There usually isn't a single fitness peak, just like there isn't a most fit organism in a population. There are large numbers of traits that can vary and still be successful. For instance, one organism may be a slow and thoughtful, another fast and impetuous. One or the other may be more successful in a given situation, but over many situations, may both be successful.

natschuster: We are talking about a population evolving into a new species.

Speciation has a number of mechanisms. For instance, in many insects, such as damselflies, the sex organs evolve into a wide variety of shapes that only fit the particular species.

If there was negative epistasis, might not that happen even if the environment changes in a different way, and evolution proceeds in a different direction? I'm just asking.

And even if there is a recombination event that moves an organism off the peak, natural selection should move to push it back on.

We are talking abotu evolution moving stepwise in a direction, towards a fitness peak. It can only go so far. Then the environment changes, and the direction changes, and the cycle repeats. The directions it evolves in are random, and it can only go so far. So there mauy be a limit to how far it can evolve.

If there was negative epistasis, might not that happen even if the environment changes in a different way, and evolution proceeds in a different direction? I'm just asking.

And even if there is a recombination event that moves an organism off the peak, natural selection should move to push it back on.

We are talking abotu evolution moving stepwise in a direction, towards a fitness peak. It can only go so far. Then the environment changes, and the direction changes, and the cycle repeats. The directions it evolves in are random, and it can only go so far. So there mauy be a limit to how far it can evolve.

nat, time to find a new shiny thing to fixate on. That argument is stupid even by your ultra-low Creationist standards.

Evolution isn't random, but the changes in the direction of evolution due to changes in the environment are. And even if the are multiple fitness peaks, there may still be negative epistasis that limits how far something can evolve.

Anyway, are the things you are saying based on empirical evidence? I was asked to provide reasons why evolution canonly go so far, and to back it up with evidence, or it doesn't count. I'm just asking.

Evolution isn't random, but the changes in the direction of evolution due to changes in the environment are. And even if the are multiple fitness peaks, there may still be negative epistasis that limits how far something can evolve.

Evolution can only go so far in any specific non-changing environment But there are no limits to how much or how far an environment can change. That means there are no limits to the cumulative effects of evolution because there are an unlimited number of potential fitness peaks to explore.

Anyway, are the things you are saying based on empirical evidence?

Yes. You've already been given dozens of papers that you refused to read, and multiple scientific websites that you refused to visit. Why do you now complain when it's you who keep choosing to remain willfully ignorant?

I was asked to provide reasons why evolution canonly go so far, and to back it up with evidence, or it doesn't count. I'm just asking.

That's right. That's why when you and the other Creationist BS artists get called on your guff you can never produce.

But if negative epistasis even when the fitness peak changes, then that means that there may be a limit to how far evolution can go in any direction. And I keep on reading that evolution is constrained by the fact that there are only so many combinations a genome can change, so it isn't infinite. Even if there are an infinite number of fitness peaks history constrains how where it can go. I think S.J. Gould said something to that effect.

But if negative epistasis even when the fitness peak changes, then that means that there may be a limit to how far evolution can go in any direction.

And monkeys whistling la Marseillaise may fly out of your butt too. Sorry squiddy, but unless you can demonstrate this magic barrier that magically limits evolution even when the environment changes you got a whole lotta nuthin'.

And I keep on reading that evolution is constrained by the fact that there are only so many combinations a genome can change, so it isn't infinite.

I don't recall anyone saying the genome could have infinite combinations or there being infinite fitness peaks. Is that going to be your new lie this week?

natschuster: Evolution isn't random, but the changes in the direction of evolution due to changes in the environment are.

The environment isn't random.

natschuster: And even if the are multiple fitness peaks, there may still be negative epistasis that limits how far something can evolve.

As we said, and will say again, the landscape is multidimensional. There is usually no singular peak for fitness, which is why populations generally consist of a great variety of organisms, most of which are quite fit within their environment.

natschuster: I was asked to provide reasons why evolution canonly go so far, and to back it up with evidence, or it doesn't count.

We know that evolution can go from land vertebrates to whales, or from primitive apes to humans. What else did you want?

Cornelius G. Hunter is a graduate of the University of Illinois where
he earned a Ph.D. in Biophysics and Computational Biology. He is
Adjunct Professor at Biola University and author of the award-winning Darwin’s God: Evolution and the Problem of Evil. Hunter’s other books include Darwin’s Proof, and his newest book Science’s Blind Spot
(Baker/Brazos Press). Dr. Hunter's interest in the theory of evolution
involves the historical and theological, as well as scientific, aspects
of the theory. His website is http://www.darwins-god.blogspot.com/